Method of recovering metals

ABSTRACT

Copper is recovered from ores, or slags, or tailing piles, in which the cupriferous material is finally subdivided by leaching with a dilute aqueous acidic leach solution, the leach solution separated from insolubles, and the copper extracted using as extractant a long chain alkyl quinaldinic acid, such as 6dodecylquinaldinic acid, in an organic solvent system, such as 75/25 kerosene/aromatic petroleum fraction and which may contain up to 25 percent of a C9 to C14 alkanol, the organic extractant in solution separated from the aqueous leach solution, and the copper stripped from the organic extractant by strong sulfuric acid, the copper being stripped as copper sulfate in acid solution, from which copper is recovered as electrolytic grade copper by electrolysis. New quinaldinic acids and methods of synthesis are disclosed.

United States Patent Pang [4 1 Jan. 25, 1972 METHOD OF RECOVERING METALSPrimary Examiner-40h" Mack Assistant ExaminerR. L. Andrews [72]Inventor: M chael Pang, Stamford, Conn. Attorney samue| Branch walker[73] Assignee: American Cyanamid Company, Stamford,

Conn [57] ABSTRACT [22] Filed; Sept 11 1969 Copper is recovered fromores, or slags, or tailing piles, in which the cupriferous material isfinally subdivided by PP Nod 356,960 leaching with a dilute aqueousacidic leach solution, the leach solution separated from insolubles, andthe copper extracted [52] U.S. Cl ..204/l06 using as exuactam a g chainalkyl qllinaldinic acid such as [5 1] Int CL .mczzd 1/166-dodecylquinaldinic acid, in an organic solvent system. such [58] Fieldat Search ..204/l06-l08- 75/25 Petmleum 260/270 23/340 may contain up to25 percent of a C to C alkanol, the organic extractant in solutionseparated from the aqueous leach 56] References Cited solution, and thecopper stripped from the organic extractant by strong sulfuric acid, thecopper being stripped as copper UNITED STATES PATENTS sulfate in acidsolution, from which copper is recovered as electrolytic grade copper byelectrolysis. 333231333 51822 Z2322?:13:1:3:1::1:13:11::313111333831182New quinawinic acids and methods ofsymhesis disclosed- 5 Claims, 1Drawing Figure PA ENT? Jmmsmz 3,637,476

AQUEOUS ACID FOR LEACHI/VG ORE BED '-AOuEOus COPPER LEACH SOLUTIONSTRONG F/L TEE SUL FUR/C 40/0 (OPTIONAL) v COPPER LOADED CHELATESOLUTION I I L LIQUID-LIQUID COUNTERCURREIVT sxmncrox? STR/PPEI? AREGENERATED ORGAN/C SOLVENT n AQUEOUS ACID SOLUT/ON 0F ALKYL T0 LEAOU/NALD/N/C 40/0 ELECTROLYTIC GRADE COPPER STRONG ACID SOLUTION OFCOPPER SULFATE +0 GAS ELECTROLYTIC CELL RECYCLE STRONG ACID INVENTOR.MICHAEL PANO ATTORNEY 1 METHOD OF RECOVERING METALS BRIEF SUMMARY Thisinvention relates to the treatment 'of copper-containing ores and orefractions, including slags, particularly processes in which copper isleached by aqueous acid, particularly sulfuric, and is extracted fromthe acidic aqueous leach solution with an oil-soluble, water-insolublelong chain alkyl quinaldinic acid dissolved in a water-insoluble organicsolvent, and more particularly in which the raffinate from the.extraction is recycled to leaching, and the extract is stripped ofthecopper with more concentrated aqueous acid, with recycling of theorganic solvent containing the long chain. quinaldinic.acid,.

and to methods of making such acidsya'nd the quinaldinic. acidsthemselves.

At present copper sells about 45 to 50 cents perpound.

Even though the value per pound of the. long chain alkyl quinaldinicacid is considerably greater than that of the copper, losses during theprocessing are kept minimal, with a very economicaloverall cost ofrecovery as comparedwith other known methods of copper beneficiation.

Solvent extraction for copper recovery is described in Lower, US. Pat.No. 3,429,694 Recovery'of Copper and Cyanide from Solutions Thereof BySolvent Extraction. Recovery by solvent extraction from acid circuits isgeneralized in Cahalan, Solvent Extraction of Copper Recovery Some.General Considerations, Chemistry and Industry, 610 Apr. 15, 1967). Chem& Eng. News, (Apr. 17, I967 lon Exchange Recovery of Copper Promising,mentions certain oximes as extractants, as does US. Pat. No. 3,244,873,Swanson, Liquid-Liquid Recovery of Copper Values using a-Hydroxy Oximes.Netherlands Pat. application No. 6,610,314 (priority claimed of US. Ser.No. 432,903 of Feb. 15, 1965) discloses other hydroxybenzophenoximes insolvent extraction of copper.

Quinaldinic acids have been described; for instance Majumdar,Quinaldinic Acid as a Reagent for the Separation and Determination ofCopper and Cadmium, Analyst, 64, 874 to 876(1939) shows quinaldinic acidas an analytical reagent. Pertinent references are cited.

Popp, Reissert Compounds, Advances in Heterocyclic Chemistry, vol. 9,Academic. Press, New'York (1968) is a review article with 63 references,mentioning among other methods, certain syntheses of quinaldinic-typecompounds.

Where not otherwise limited by context, the term ore fraction" isintended to include the ores themselves, in place or as mined, crushedor ground to treatable size, both rich and lean, as well as selectedportions such as fines or slimes from any of the grinding operations,before or after flotation, sands or any sands fractions of any size inwhich the reduction of ore particles is small enough that an economicfraction of the copper? containing minerals are exposed to action byreagents, also cleaner tailings, rougher tailings, rougher.concentrates, cleaner concentrates, and slags, including converter slagsand reverberatory slags. With slags, grinding or other methods ofattrition may be necessary in order that the subdivision be fine enoughto permit attack on the individual copper-bearing'particles by acidsolution.

The ore fraction may contain both sands and slimes; The slimes are thefinely divided, difficulty filterable particles, which frequently aredifficult to handle because of the large surface to weight ratio. Sandsare larger particles, usually from a classification step, frequentlyusing a cyclone, and are more amenable to flotation. Hence, circuits areuseful in which the slimes are treated directly with acid leaching, andthe sands are floated, with part or all of the concentrate sent to thesmelter as in conventional processing, and with part of the tailings, orcleaner tailings being treated by acid leaching.

Ores may be leached in placewithout mining by injecting water and/oracids such as sulfuric into copper bearing formations. The resultingacidic copper-bearing solutions are collected by various methods and aretreatedby the extractants treated.

The economics of leaching of each copper-bearing ore or orefraction maybe separately considered. The preferred circuit varies with the type ofore treated, the richness of ore, and cost and availability of water,acid, the organic solvent and the long chain alkyl quinaldinic acidextractant. The most economical circuit for a specific ore or orefraction can be chosen using the principles set forth herein as appliedto the conditions that prevail at a specific ore processing operation.

The present process gives best results with oxide ores, and ores thatare easily oxidized.

One very useful process is to leach tailing piles with dilute sulfuricacid, with the aid of bacterial action, and by percolation .of acidthrough the tailing piles. The process may take years. More rapidleaching is sometimes preferred as in vat leaching or by agitating theore fraction in acidic solution.

Acid' extraction is useful in flow sheets in which sulfide copper isfloated, and residual oxide copper is acid leached, as well as inprocesses in which sulfides are oxidized to the copper oxides byroasting, or slow oxidation at ambient tern 'peratures. Some forms ofsulfide copper are dissolved in dilute acids at rates which areattractive, without further treatment. Bacterial action aids theleaching operations.

As used herein, the term sulfide ores" includes those containing themore common sulfide minerals, such as chalcocite (Cu S), digenite (Cu Sand covellite (CuS), as well as mixed sulfides such as bornite (CuFeS.,), enargite (Cu,,AsS.,), and tetrahedrite (Cu, Sb,S, Chalcopyritealso may be present.

The term oxide ores" is used to cover the ores in which the copperoccurs as an oxide or carbonate such as azurite (Cu- CO -Cu(OH)malachite (Cu (OH) Co cuprite (Cu- 0), tenorite (CuO) and forms ofchrysocolla, which is a silicate mineral of copper.

The term mixed ores" is used to cover ores in which the copper occurs asboth sulfide minerals and oxide minerals and the proportion of each islarge enough that for reasonable economic recovery both types of copperminerals need to be considered in the treatment. Sulfide ores which arecompletely free from oxide, or oxide ores which are completely free fromsulfides are unusual. Ores exist in which the proportion of oxides in asulfide ore or sulfide in an oxide ore is so low that for metallurgicalrecovery purposes the ore may be considered as essentially the sulfideor an oxide type. Similarly, in working with slags the sameclassification can be used and in working with ore fractions the sameterminology is applicable.

Similarly, scrap metal, or metal containing industrial waste productsmay contain enough acid soluble copper that recovery of the copper iseconomical, such scrap, or metal may be considered an ore for presentpurposes.

The acid in which the copper is dissolved, called the leach acid, isusually a dilute sulfuric acid, not necessarily pure. Other low-costacids, such as hydrochloric acid, or nitric acid can. be used. Becausesulfuric acid is usually lowest in cost, sulfuricacid is the leachingacid of choice. As described below, part of the acid may be recycled tothe process, andpart of all of the acidcan be produced in oreprocessing. For example, sulfide ores may be roasted and the sulfurrecovered as sulfur dioxide or converted to sulfuric acid, and the acidas so recovered may be used for leaching ore fractions.

Particularly in leaching ore piles such as tailing dumps, and overburdencontaining low-copper values, the rapidity of leaching is not important,and slow percolation of dilute acid over a period of months or yearsgives good results. For such slow leaching, a dilute acidat a pH of l to6 gives good extraction. More concentrated acid solutions give fasterleaching. A warmer leaching acid extracts the copper more rapidly, andhas lower viscosity, but usually the leaching is carried out at ambienttemperatures, without added heat. Such temperatures can be from justabove freezing to over F. (38 C.) during the summer or in the tropics.

Theorganic phase for the extraction must be water insolu ble andpreferably very insoluble to reduce losses. The solubility in water at25 C. should be below about 0.1 percent and preferably below 100 partsper million reduced losses in the aqueous phase being extracted. Afraction which is more soluble may be used if available at a price thatmakes losses, including losses of the said quinaldinic acid, acceptable.The specific gravity needs to be different from the aqueous phase topermit fast phase splitting. Theoretically, a fraction heavier thanwater can be used, but economically present prices dictate solventslighter than water. A specific gravity of less than 0.9 is preferred forfast separation; even lower gives faster separation. The organic phaseshould be a liquid at the temperature of operations and for economicoperations must be low in cost.

Theoretically, liquid aliphatic hydrocarbons, pure or mixed, includingcycloaliphatic hydrocarbons and aromatic hydrocarbons, includingarylalkyls are satisfactory. Chlorinated or other halogenated comparablesolvents may be present in the solvent.

From cost considerations aliphatic fractions from petroleumdistillation, such as kerosene, are most advantageous. Monocyclicaromatic fractions, such as benzene, mixed xylenes, and toluene, andpetroleum fractions containing some proportions thereof give improvedsolubility to the long chain quinaldinic acid and its copper chelates.Fuel oils are often advantages commercially. If more volatile thankerosene, the flammability and loss by volatilization becomes high andif must higher boiling that the kerosene range, the viscosity becomeshigh and, hence, disadvantageous. Among the aromatics, aromaticfractions from petroleum distillation, are economically advantageous.Preferably fractions are used with a flash point above operatingtemperatures.

These materials are available under such trade names as Varsol,Solvesso, etc. Pure materials give excellent results but the choice isusually the cheapest available organic solvent, usually a mixture andnot particularly pure, often a petroleum fraction of mixed aliphatic andaromatic compounds; A solvent of low flammablity is preferred to avoidfire hazards. Kerosene has a boiling point of about 150 to 300 C. whichis a boiling point high enough to keep evaporation losses withinreasonable limits. The aromatic petroleum fractions in the same boilingpoint range are versatile and useful when available at a competitiveprice.

A mixture of kerosene and an aromatic petroleum fraction is botheffective and economical. From the standpoint of extraction efficiency,benzene, toluene and low-boiling kerosene is very effective but may be afire hazard.

Commercially available aromatic petroleum fractions with a flash pointof over about 125 F. (52 C.) are better from the fire hazard viewpoint.In general, the flash point of the solvent system in use should be atleast 100 F. (38C.) and preferably 125 F. (52 C.).

Ethyl ether is an excellent solvent for the organic extractant, and butfor the fire hazard could be used advantageously. Because ethyl ether isso very flammable, its use in large scale commercial operations isavoided.

An intermediate chain length alkanol, that is one with from about nineto 14 carbons in the alkanol, and commercial mixtures thereof aid inkeeping the long chain alkyl quinaldinic acid and its chelates insolution. Up to 25 percent by weight can be used. Usually from about 5to percent aids in solubilization, at lowest costs. Decanol with a flashpoint of about 356 F. 180 C.) is available in commercial grades and isused advantageously. lsodecanol and dodecanol are also commerciallycompetitively priced and useful.

Optimum operating conditions vary with various ores, leach acids copperconcentrations, and long chain quinaldinic acid concentrations.

The organic extractant and its copper chelates must be soluble in theorganic carrier solvent. The water solubility of the organic extractantand its copper chelates should be less than about 50 parts per millionand preferably less than about 10 parts per million, to avoid unduelosses.

The organic extractant should be nonemulsion forming so as to allowrapid and clear phase separation of the organic layer from the aqueouslayer. Phase separation times of less than 5 minutes are desirable butunder certain conditions longer times may be tolerated depending onlocal conditions, including tonnage throughput and the nature and sizeof extracting equipment available. A centrifuge aids in removing thesmaller particles of the organic solvent rapidly.

One of the classic reactions for organic chemistry is the Skraupsynthesis in which aniline is heated with glycerol and nitrobenzene inthe presence of sulfuric acid to yield quinoline. substitutedquinolines.

It has now been found that substituted anilines in which there are oneor more alkyl groups in the 3, 4, or 5 positions also may be reactedunder similar conditions to yield quinoline. Depending upon the size ofthe vessel, heat may be generated so vigorously that external cooling isrequired to maintain the temperature at that desired, or in otherconditions the heat losses from the equipment will be such that heatmust be added. Because glycerol is dehydrated to acrolein, it wouldappear from theory, and appears in fact, that acrolein can be used inthe syntheses; however it is preferred that glycerol be used as startingmaterial and the dehydration occur in situ. Conveniently the sulfuricacid is put in the reactor and a mixture of the substituted aniline,glycerol, and nitrobenzene added thereto with stirring. The vigor of thereaction depends in part upon the substituents on the the aniline andmay occur from near room temperature to around 135 C. Frequently it isconvenient to add the reactants at below C. preferably around 60 to 90C. and then heat to between and C. to complete the reaction. After thereaction, the residual nitrobenzene is removed as for example by steamdistillation, additional water added and the aqueous layer discarded.The organic product may be washed with caustic to neutralize anyresidual acid.

The conditions described are unique to the preparation of long chainalkyl quinolines. 1n the original Skraup synthesis, concentratedsulfuric acid (96 percent) is added slowly to a mixture of aniline,nitrobenzene, glycerol, boric acid and fer rous sulfate. When thisprocedure is employed with long chain alkyl anilines, the reactionmixture gels during the sulfuric acid addition. This gelation presentsmechanical stirring problems and may result in a hazardous condition,particularly in large scale operation, in which it is difficult tocontrol the highly exothermic Skraup reaction. Moreover, the presence ofreaction moderators such as ferrous sulfate and boric acid isundesirable because because the product long chain alkyl quinoline isnot readily steam distilled out of the reaction mixture. Thesedifficulties are prevented by reversing the order of addition and byusing 80-85 percent sulfuric acid, preferably about 82 percent. Theseconditions avoid gel formation; thus, the synthesis can be carried outsmoothly by adding a mixture of nitrobenzene, glycerol and alkyl anilineto 82 percent sulfuric acid.

The alkyl quinoline is dissolved in a solvent such as methylene chlorideor other inert solvent and stirred with an aqueous solution of sodium orpotassium cyanide. To the stirred mixture is added benzoyl chloride.This is a classic Reissert reaction. The cyanide adds to the 2 positionwhile the benzoyl group adds to the nitrogen. After this reaction iscompleted, the reactor may be cooled, the mixture stirred with water andthe aqueous layer separated and discarded. To the organic layer is thenadded concentrated hydrochloric acid slowly at about room temperature,followed by heating to 75-90 C. for l-4 hours to effect hydrolysis ofthe nitrile to the carboxylic acid group. The product alkyl quinaldinicacid can be separated by distilling off the benzaldehyde by steamdistillation, discarding the aqueous layer, dissolving the thus formedquinaldinic acid in a solvent such as hexane, washing with caustic, thenacid, and then water to obtain the alkyl quinaldinic acid.

The product alkyl quinaldinic acid can also be conveniently isolated bysteam distilling the hydrochloric acid-organic layer which effects thehydrolysis reaction and the removal of benzaldehyde simultaneously. Thisone-step process has the additional advantage over the two-stepheating-distilling process of minimizing the formation of byproductbenzoin.

The sum totals of the carbons in the 3, 4, and 5 positions of theaniline should be between about 6 and about 30. The alkyl groups can bebranched and but for cost considerations could have substituents such aschlorine or alkoxy groups thereon. Any groups which do not impair theoil solubility and are inert 5 under the conditions of extraction ofcopper are acceptable but from cost considerations it is usual to haveonly the six to 30 carbon alkyl substituents. A substituted glycerolcould be used so that a product is obtained which also has a substituentin the 4 position on the product quinaldinic acid; however the presenceof substituents on the glycerol complicates the yields in the syntheses.The reactions may be illustrated by the following equations:

(l ll i R ou. CHOU +IIzSO I R- at on CH OII R R R2 CHOH then,

GHsNOZ RE I IIZSOJ R1 R2 II then,

2 COCl GU30]: R CN NaCN H O R R2 III than,

(4) R oooH Acid As is obvious, the long chain alkyl quinaldinic acid canbe a mixture of alkyl quinaldinic acids. A convenient starting materialfor commercial syntheses is a technical or crude grade ofp-dodecylaniline. As commercially available this material has aplurality of different alkyl groups in the para position ranging fromabout six to 18 with an average of about 12. Some of the commercialgrades have at least percent of dodecylaniline in the technical grade. Apure compound, or a mixture of pure compounds may be used, but as costconsiderations in copper refining are extremely important, the lowercost technical grades are normally used and area mixture ofvariousp-alkyl anilines. The chelating ability is a molar function andhence the larger the alkyl groups, the lower the chelating capacity perpound of the long chain quinaldinic acid; on the other hand theintroduction of additional alkyl groups appears to aid solubility in theoil phases. An effective compromise occurs at about the p-dodecylquinaldinic acid and hence, because of this and the commerciallyavailablility of the technical grade p-dodecyl aniline as a startingmaterial, such material is usually the starting material of choice.

DRAWINGS solving the copper. Copper oxide ores are more readilydissolved than the sulfide ores, but bacteria and ambient atmosphericoxygen tend to aid oxidation of sulfide ores to facilitate leaching.Some of the sulfides are themselves soluble in acids, When theextraction is from an ore bed which is leached by percolation, extendedperiods of years may be used for the leaching and hence slow oxidationis satisfactory. Strong acids leach more rapidly, but on the other hand,strong acids are more expensive, so that acids at a pH from around 1 to5 are frequently used for leaching.

The aqueous copper leach solution may be filtered if there are finespresent, and then fed to a liquidJiquid extractor in which the copper isextracted as a chelate of the alkyl quinaldinic acid dissolved in thesolvent phase. A counter current extractor is preferred in order thatthe fresh organic solvent containing the alkyl quinaldinic acid extractsfrom the acid solution having the lowest copper and as the copperloading of the organic phase increases it comes in contact with thefresher and hence higher copper concentrations in the aqueous acid leachliquor. As the quinaldinic acid forms a chelate with the copper, protonsare released and these, together with the sulfate ions or other anionsin the leach solution remain in such solution and reform the acid sothat the leach solution becomes more acidic, and the regenerated aqueousacid may again be recirculated to leach additional ore. More diluteacids are used on the lower grade ore beds and wash water may be used torecover some of the acid from the ore beds. Depending upon the watercontent of the ore beds in which initial leaching occurs, ambientrainfall and other conditions, the total circulating acid may build upand if a build up occurs, the more dilute acids containing a minimum ofcopper may be discarded.

The copper loaded chelate solution is passed to a second liquid-liquidextraction system which is also a counter current type in which a strongacid, such as about 15-20 percent or stronger sulfuric acid isintroduced counter current to the copper loaded chelate solution withappropriate mixing to insure agitation and hence stripping. The strongacid dissolves the copper as copper sulfate and is passed to anelectrolytic cell. The copper sulfate is electrolyzed, regeneratingsulfuric acid and yielding an electrolytic grade of copper. The acidproduced by the electrolytic cell is recycled with additional makeupacid added as required to the stripping column.

Normally the organic phase is adequately separated in the countercurrent stripping system but if complete separation does not occur, anadditional amount of organic solvent can be added and the organicsolvent used as a wash to protect against loss of the long chain alkylquinaldinic acid which is the most expensive component of the recoverysystem.

Filters or centrifuges and flotation equipment may be used to aid in ahighly effective recovery of the organic phase. The ratio of the longchain alkyl quinaldinic acid, hereafter in part abbreviated AQA, in thesolvent phase may be from less than about 1 percent to more than 20percent. It is desirable that the quantity of the AQA be less than thatsoluble in the solvent to avoid possible losses, and around 5 percent isfrequently an economic maximum. The AQA and its copper chelate must besoluble in the solvent under the conditions of use. If the extraction ismade in very cold weather, the concentration may be less than when thetemperature is higher.

The total volume of AQA loaded organic solvent needs to be such that thechelating ability of the AQA is sufficient to remove all of the copperin the copper leach solution. Depending upon the copper concentration,this can be from around 25 percent of the volume of the leach solutionor if the copper load is low it may be down to 5 percent or 1 percent orless. The counter current extraction system permits effective loadingwith a high percentage of the theoretical copper content based on theAQA content.

The copper is extracted from the copper containing solvent phase bysulfuric acid preferably at least about l5-20 percent and which may runup to 50 percent or more. Around 20 to 30 percent gives good results andis a good feed for an electrolytic cell in which the copper is recoveredby electrolysis.

AQA is selective toward copper and leaves iron and many othercontaminants relatively unextracted in the leach solution. Both thespecificity towards copper and the high recovery of AQA insure aneconomical process for the extraction of copper.

Frequently, it is desirable to float sulfide copper from an ore andtreat the tail or other low-grade materials, by an acid leach. Thisreduces the volume of circulating acid leach solution and the AQA inorganic solvent circulating load. If the ore is roasted, all of thecopper may be effectively recovered by the AQA organic solventextraction of the acidic leach solution.

By way of illustration but not limitation, the invention is set forth inthe following examples in which all parts are by weight and temperaturescentigrade unless clearly otherwise stated:

EXAMPLE 1 Preparation of 6-Dodecyquinoline Introduce 830 parts, byweight, of 82 percent sulfuric acid into a reactor equipped with anefficient stirrer. Mix 522 parts of p-dodecylaniline, 313 parts ofglycerol and 148 parts of nitrobenzene and add to the reactor containingthe diluted sulfun'c acid, while stirring. The reaction temperaturerises rapidly. The addition rate of theP-dodecylaniline-glycerolnitrobenzene mixture is controlled so that thereaction temperature stays between 70 and 80 C.; with external coolingbeing used to control the temperature rise. The addition takes about 30minutes. The reactor is heated to between 130 and 140 preferably at 135and maintained at this temperature for 6 to 8 hours. Then steam isintroduced into the reaction mixture to steam distill out all theunreacted nitrobenzene. After the steam distillation, add 500 parts ofwater, mix thoroughly, and then allow to stand. The aqueous acidicsolution, which is the lower layer is removed and discarded. The organicproduct is washed with another 500 parts of hot water. Enough percentcaustic is added to the organic product slowly with rapid stirring sothat the reaction mixture becomes basic to litmus. Allow to stand. Theaqueous phase separates and is discarded. Wash the product with 500parts of hot water. A yield of 595 parts is obtained, of which 74percent is 6-dodecylquinoline, and 26 percent is p-dodecylaniline.

EXAMPLE 11 Preparation of 6-Dodecylquinaldinic Acid Introduce 29.75parts by weight of distilled 6-dodecylquinoline and 67 parts ofmethylene chloride into a reactor equipped with an efficient stirrer.Dissolve l 1.7 parts of potassium cyanide (KCN) in 16 parts of water andadd to the reactor. Stir vigorously while adding a solution of 25.2parts of benzoyl chloride in 13.4 parts of methylene chloride over aperiod of 20 minutes, maintaining the temperature at about C. during theaddition, and while stirring for an additional hour. 100 parts of wateris added, and mixed thoroughly. Allow to stand so that the aqueoussolution separates, then discard the aqueous layer. Cool the organiclayer to 20 C. Then add 100 parts by weight of concentrated HCl slowly,maintaining the temperature at 2030. Steam distill to remove allbenzaldehyde and hydrolyze the nitrile group, then dissolve in about 100parts by volume of hexane. Wash with 100 by volume portions of 20percent caustic until the used wash liquor is basic to litmus. Then washover the dilute hydrochloric acid until the used wash liquor is acid tolitmus. A yield of 33 parts of 6-dodecylquinaldinic acid is obtained.

N coorr EXAMPLE [[1 Stir a mixture of 148.7 parts of vacuum distilled 6-dodecylquinoline and 330 parts of methylene chloride in a reactor.Dissolve 44.1 parts of sodium cyanide in 80 parts of water and add tothe above. Add a solution of 126 parts of benzoyl chloride in 65 partsof methylene chloride to the reactor at such a rate that the reactiontemperature does not exceed 50 C. Cool to room temperature and add 238pans of concentrated HCl. Heat at about 75-90 for 4 hours. Steam distillthe mixture to remove benzaldehyde, and hydrolyze, and then remove anddiscard the aqueous portion. Dissolve the organic portion in about 500parts of ether. Wash the etheral solution twice with 100 part portionsof 10 percent caustic and then three times with 100 part portions of 5percent caustic. Wash the ethereal solution with dilute HCl until thewash liquor is acid to litmus. Wash once with 500 parts of water.Evaporate the ether to yield 93.7 parts of product. Analysis of theproduct obtained in this manner shows that it contains 78.9 percent-dodecylquinaldinic acid, 7.4 percent 6-dodecylquinoline, 3.4 percentbenzoic acid and 8.2 percent benzoin.

EXAMPLE 1V Into a reaction vessel, introduce in the following order: 28grams of ferrous sulfate (FeSo '7H O), 59 grams of nitrobenzene, l 10grams of p-dodecylaniline. Heat a mixture of 50 grams of boric acid and250 grams of glycerol to effect solution; cool to room temperature andadd to the the contents of the reaction vessel. Mix thoroughly bystirring. Then add 258 grams of concentrated H slowly to avoid frothingand overheating by the exothermic reaction. The reaction mixture gels.Heat the reaction vessel until the mixture begins to boil (145 C.)Continue heating and allow the reaction to run for 4 hours at 132 and 15hours at 125. Without cooling, steam distill until the distillate isfree from nitrobenzene. Cool the mixture in the reaction vessel, and addenough 50 percent caustic to make the solution alkaline. Filter thereaction mixture and extract the filtrate with hexane. Evaporation ofhexane from the extract yields 38 grams of 6-dodecylquinoline.

EXAMPLE V Dissolve 4.06 parts of KCN in 25 parts of water and pour intoa reaction vessel containing 7.7 parts of 6-dodecylquinoline fromexample lV. Add 4.2 parts of benzoyl chloride carefully and heat themixture to 70 for 15 minutes, then cool to room temperature. Add 20parts by volume of benzene, 20 parts by volume of water and then 20parts of concentrated HCL. Stir the reaction for 20 minutes and allow tostand until the phases separate. Collect the upper layer and evaporatethe benzene under vacuum. A yield of 8.3 parts remains of the darkviscous oil, which is 6-dodecylquinaldinic acid.

EXAMPLE Vl Introduce 80 grams of benzene and 5 grams of AlCl into areactor. Heat, and while stirring, add slowly 147.5 grams of C1510a-olefin at such a rate that the reaction temperature does not exceedcool to room temperature. Add water to the reaction mixture carefully todecompose residual AlCl Distill out excess benzene. The produce (alkyl Cbenzene) weighs 156 grams.

To the alkyl benzene in a reactor, add a cold mixture of 50 grams ofconcentrated nitric acid and 50 grams of concentrated sulfuric acidslowly such that the reaction temperature does not exceed 50, After theaddition, heat the mixture for 30 minutes at 50, then cool to roomtemperature, and and pour the mixture into a beaker containing crushedice. Extract the product with ether. Evaporation of the ether yields 17]grams of p-nitro-alkylbenzene.

Mix 107 grams of p-nitro-alkylbenzene with grams of concentrated HCl Add10 grams of SnCl '2H 0 and heat the reaction mixture to a temperature of65. Add 190 grams of SnCl -2 O slowly and after the addition, rise thetemperature to 95. Hold for 40 minutes at 95, then pour the reactionmixture into milliliters of 40 percent NaOH in crushed ice. The crudep-alkylaniline weighs 1 10 grams.

Introduced into a reactor in order: 10.5 grams of FeSo -7H 0, 85 gramsof the p-C,.,- aklylaniline prepared above, and 23.6 grams ofnitrobenzene. Heat a mixture of 20 grams of boric acid and 112.5 gramsof glycerol to effect solution; cool to room temperature and add to thereaction vessel. Add 97 grams of concentrated H 80 slowly. The reactionmixture gels. Heat the mixture to boil and then allow to cool to roomtemperature and is extracted with 500 grams of ether. Wash the etherealextract with 200 milliliters of 20 percent NaOl-l Evaporation of etheryields 91 grams of crude 6alkylquinoline.

Dissolve 2.6 grams of KCN in 20 milliliters of water. Mix grams of theabove 6-alkylquinoline with the KCN solution. Add 3.5 grams of benzoylchloride slowly and after addition, raise the reaction temperature to50. After minutes of heating, add 30 milliliters of concentrated HC] andheat the reaction for 30 minutes at 70. Add about 50 milliliters each ofwater and either. Collect the organic layer and wash it with 50milliliters of concentrated HCl and then 50 milliliters of water.Evaporation of ether yields 10.2 grams of 6-C -alky1quinaldinic acid.

EXAMPLE Vll lntroduced into a reactor in the following order: 56 gramsof FeS0 -7H 0, 220 grams of p-dodecylanilne, 60 grams of nitrobenzeneand 140 grams of glycerol and 300 grams of concentrated H 80 slowly. Thereaction mixture gels. Raise the temperature to boil (155) and thencontinued heating for 2 hours at 140. Steam distill to remove excessnitrobenzene, then discard the aqueous layer. Extract the productmixture with about 500 grams of ether. Wash the ether solution with 400milliliters of water, 400 milliliters of 10 percent NaOH and then twicewith 400 milliliters of water. After the distillation of ether, vacuumdistill and collect the fraction between l301400.05 mm. The6-dodecylquinoline obtained weighs 192 grams.

Mix 150 grams of the 6-dodecylquinoline, 15 milliliters of benzene, 50grams of NaCN in 200 milliliters of water, then add 140 grams of benzoylchloride. Cool to room temperature and add 300 milliliters ofconcentrated HCL. Raise the temperature to near boiling, (90) and allowto react for 1 hour. Steam distill to remove benzaldehyde. The hotmixture is transferred to a separatory funnel where the organic layer isseparated out. Wash with 500 milliliters of 1 percent NaOH and then 5times with 500 milliliters portions of hot water. Dissolve the productin 500 grams of ether. Wash the ethereal solution twice with 300milliliters of water. Evaporation of ether yields 170 grams of6-dodecylquinaldinic acid.

EXAMPLE VIlI lntroduced 130.7 grams of p-dodecylaniline, 33.2 grams ofnitrobenzene and 69 grams of glycerol into a reactor. Stir thoroughly.Add milliliters of 76 percent H S0 slowly. The reacting mixturethickness and then thins out during the reaction. Heat to 138-145 andhold for 7 hours. The product is steam distilled until all thenitrobenzene is removed. Cool to room temperature. Add 300 millilitersof hexane and grams of NaOH in 200 milliliters of water. Mix thoroughly,and then allow to stand, discard the aqueous layer, then wash twice with300 milliliter portions of water. Evaporation of the hexane yields 144grams of 6 -dodecylquinoline. Vacuum distillation yields 132 grams ofpure material.

Dissolve 3.68 grams of NaCN in 8 milliliters of water. Add 14.8 grams ofthe distilled 6-dodecylquinoline and 8 milliliters of methylenechloride. Mix thoroughly and add 9.14 grams of benzoyl chloride. Raisethe temperature to 60 and hold for 20 minutes. Add 20 milliliters ofconcentrated HCl and heat for minutes at 90. Wash the product threetimes with 100 milliliter portions of hot water. Steam distill to removebenzaldehyde. The yield of 6-dodecylquinaldinic acid is 16.8 grams.

EXAMPLE lX Mix thoroughly 354 parts by weight of distilled 6-dodecylquinoline with 650 parts of methylene chloride and a solution of102 parts of NaCN in 130 parts of water in a reactor, then add 284 partsof benzoyl chloride, at such a rate that the reaction temperature doesnot exceed 40 C. Allow to stand at room temperature for 24 hours. Mixthoroughly with 200 parts by weight of water and allow to stand, toseparate. The aqueous layer is discarded. Add 238 parts by weight ofconcentrated HCl and then raise the temperature to 70-80 C. for 1 hour,then steam distill until the mixture is free from benzaldehyde. Cool theproduct, and then dissolve in 600 parts of hexane. Wash the solutionwith 100 parts of 5 percent caustic until the wash the liquor is freefrom sodium benzoate. Reacidify the product with 500 parts of 6 N HCland then wash once again with 400 parts water. On standing a solidprecipitates out and is isolated yielding 62 parts of product.

Recrystallization with a methanol-water mixture yields 57 parts of whilesolid which melts at 99101 C. Elemental analysis shows that it containsC77.29 percent, H 9.79 percent and N 4.22 percent (theor. for6-dodecylquinaldinic acid C 77.37 percent; H 9.15 percent and N 4.10percent). Gel permeation chromatography shows that it has a minimumpurity of 98 percent as 6-dodecylquinaldinic acid.

EXAMPLE X Mix 1001 grams of distilled 6-dodecylquinoline, 1056 grams ofmethylene chloride and solution of 3.77.4 grams of KCN in 500 grams ofwater. Cool the mixture to 20 C. and add a solution of 815 grams ofbenzoyl chloride in 264 grams of methylene chloride, as such a rate thatthe reaction temperature does not exceed 25 C. The addition taken about2% hours. Then stir the mixture for 2 hours 2025C. Wash the product with500 grams portions of water twice. Add 900 grams of concentrated HCl andmix thoroughly. Steam distill the mixture until free from benzaldehyde,discard the aqueous layer and dissolve the product in about 1 kilogramof ether. Wash the ethereal solution twice with 1 kilogram of etherportions of 20 percent caustic, then with 700 grams of water. Acidify bywashing with 500 grams portions of 6 N hydrochloric acid until the washliquor is acid to litmus. Evaporation of ether leaves 1111 grams ofcrude product. The product on analysis shows 88.3 percent6-dodecylquinaldinic acid, 6.8 percent of quinoline, 4.8 percent ofbenzoic acid and 3 percent of benzoin.

Dissolve the crude product in 3,000 grams of hexane and allow to standfor about 24 hours, The solid precipitated out is filtered and dried.Recrystallization from methanol-water yields 20] grams of white solid,which by analysis contain 94,6 percent of 6-dodecylquinaldinic acid 2.6percent of benzoic acid and 2.7 percent of benzoin.

EXAMPLE XI In a well-stirred reactor, to 830 parts of 82 percent H areadded slowly a mixture consisting of 313 parts of glycerol, 148 parts ofnitrobenzene and 522 parts of p-dodecylaniline, holding the reactiontemperature to less than 70. The reaction mixture remains fluid. Heat to138-145to hold for 7 hours.

The product is steam distilled to remove nitrobenzene. 62 parts ofnitrobenzene are recovered from the distillate. The water accumulatedduring steam distillation is separated and discarded. Without cooling,wash with 100 parts of caustic in 800 parts of water. Repeat the causticwash with fresh caustic solution if the wash liquor is acidic after thewashing. Wash the product once with 1000 parts of hot water. The crude6- dodecylquinoline yield is 624 parts of percent. The crude productanalizes as 73.7 percent 6-dodecylquinoline. Vacuum distillation over 20parts of zinc powder yields 555 parts of 79.2 percent 6-dodecylquinline.

EXAMPLEXII Mix 500 grams of p-dodecylaniline with 313 grams of glyceroland 100 grams of nitrobenzene. Add this mixture to a well-stirredreactor containing 774 grams of 88 percent sulfuric acid. The additionrate is controlled so that the reaction temperature does not exceed 70C. After about 60 percent of the mixture is added, the reaction mixturethickens and the stirring efficiency drops drastically. After theaddition the reaction temperature is raised to about 135 by externalheating. The reaction mixture begins to thin out at about 120. At 135the reaction becomes violent and external cooling is applied to controlthe exotherm. The mixture is then maintained at 138l45 for hours. Theproduct is isolated ad described in example XI. Distillation of thecrude product yields 400 graphs of o-dodecylquinoline.

EXAMPLE X111 Mix 210 grams of 6-dodecylquinoline from example X11 abovewith 600 grams methylene chloride in a reactor. Dissolve 62.5 grams ofNaCN in 80 grams of water and mix thoroughly with the 6-dodecylquinoline solution. Add 180 grams of benzoyl chloride at such arate that the reaction temperature remains below 50. After the benzoylchloride is added, raise the reaction temperature to 70 and allow thereaction to run at this temperature for 1 hour. Mix thoroughly with 200grams of water and allow to stand. Discard the aqueous layer. Add 238grams of concentrated HCl slowly and heat the mixture at 70 for 1 hour.Wash the product mixture with 100 grams of water. Add 123 grams of Nsulfuric acid and steam distill until there is no benzaldehyde in thedistillate. Discard the aqueous layer and dissolve the organic portionin 500 grams of hexane. Wash once with 500 grams of 5 percent oftrisodium phosphate solution, and then 1 19 grams of concentrated HCL.Wash twice with 500 grams portions of water. After the removal of hexaneby distillation, 161 grams of product are obtained, which analysis showscontains 85. 2 percent of o-dodecylquinaldinic acid.

EXAMPLE XIV A solution containing 1.27 grams of copper and 2.1 1 gramsof iron per liter is obtained by the extraction of an ore sample withdilute sulfuric acid. The solution has a pH of about 2.0. Portions ofthis leach solutions are extracted with an organic extractant consistingof kerosene (boiling point 150300 C.) containing 10 percent by weight ofthe product of example 11.

In one test to illustrate the selectivity of the AQA equal portion ofthe leach solution of kerosene containing 10 percent AQA were shakentogether and the residual aqueous solution was analyzed for both copperand iron by atomic absorption. To illustrate the loading of the organicphase, a single-organic phase was shaken with 5 successive portions ofthe aqueous leach solution and the loading determined by analysis of theaqueous with organic by difference after each of these shakings andfound to be:

Copper concentration lron concentration grams/liter grams/liter OrganicAqueous Organic Aqueous 1st Extraction 1.27 0.00 0.93 1.18

2nd 2.54 0.00 1.00 204 3rd 3.79 0.02 0.66 2.45

4th 4.86 0.20 0.16 2.61 5th 513 1.00 0.01 2.26

This extraction of the leach solution shows that the organic solution of-dodecylquinaldinic acid extracts copper from the aqueous solution at ahigh preferential rate until the organic phase becomes well loaded withcopper. The figures on the iron concentration shown that the AQA doesextract iron to some extent from the aqueous solution, and where theaqueous solution has substantially all of the copper extracted, iron isalso extracted but as the organic solution becomes more heavily loadedwith copper, additional copper selectively replaces iron which has beenchelated by the AQA, and the aqueous phase is actually selectivelyreloaded with iron from the organic phase. Even if the chelate doescontain some iron, copper is extracted and iron released to enrich theaqueous phase with iron, while removing copper from the aqueous phase.

EXAMPLE XV The loaded organic solution from example XIV was strippedwith a 20 percent by weight sulfuric acid solution. Equal volumes of theorganic phase and the 20 percent acid stripping phase were used. Thefollowing table shows the concentration of copper and iron left in theorganic solution after stripping with four successive portions of 20percent acid.

Concentration of iron grams/liter in organic Concentration of coppergrams/liter in organic phase phase 1st strip 2.29 0.01

EXAMPLE XVl A run was performed using leach liquor similar to that usedin example XiV but with 5 percent of AQA from example X111 to kerosene,after the AQA extract had been washed with twice its volume of 10percent caustic solution and then reacidified. At the 5 percent level inkerosene the results on extraction were found to be:

Copper concentration lron concentration A run was performed similar toexample XU extracting with 20 percent sulfuric acid the organic phasefrom the preceding EXAMPLE XVI The results were found to be:

Concentration of copper Concentration of iron grams/liter in grams/literin organic phase organic phase 1st strip 1.37 0.00 2nd 1.06 0.00 3rd1.00 0.00

In actual mining operations, the results are not readily set forth intabular from because the leach solution may be fairly concentratedcopper containing leach in a highly acid solution where a roasted ore isextracted with a fairly strong acid, down to an extremely dilutesolution containing low quantities of both copper and iron. For example,the feed may be a naturally occuring stream or water taken from a mine,or a leach solution which has percolated through a tailing pile, or acidfed through a stripped overburden which does not contain sufficientcopper to warrant mining or ore processing through a normal millcircuit, but yet which contains sufficient copper that dilute acidleaches copper therefrom, over a long period of time. As copper isoxidized from the sulfides to the oxides by bacterial action and theacid percolates slowly through the piles of copper-containing overburdena dilute leach solution containing copper is obtained. The copper leachsolution can contain from less than 9% gram per liter to 10 pr moregrams per liter of copper in the acidic aqueous phase. Usually aconcentration of around 0.7 to 1.5 grams per liter of copper is closerto conventional practice. it is to be stressed that the presentextraction is designed to work with such acidic copper containingstreams as they are found and not necessarily at concentrations whichhave adjusted for the convenience of the extraction system.

Similarly the extraction can be one that occurs naturally canyonimpermeability in a matter of hours in a leach tank or one that occursover a period of years in tailing dumps. The leach bed can be a natuallyoccuring canyon (or one in which an asphalt lining has been placed onthe surface to give improved water impermeability with an entire canyonfilled; and the leaching occuring over a period of years through theentire canyon containing millions of tons of low-copper contentminerals.

Variations in the conditions of the leaching, the countercurrentextraction, and the stripping are readily adjusted to maximize theeconomic recovery from particular ore beds which are available forprocessing at a particular time and plate. Such variations are withinthe scope of the present invention.

The ratio of the weights of extractant in the organic solvent, that isthe AQA in the water immiscible solvent phase, to the aqueous copperleach solution may vary widely. If the copper concentration is high,obviously a larger volume of the AQA- solvent is required to extract thecopper than if the copper concentration is comparatively low. The numberof stages of counter current extraction varies with the type ofequipment, and other flow sheet details. For conventional-typeextractors, from three to nine stages normally can be considered as aneconomical range for either the AQA-solvent extraction of the copper, orfor the strong acid stripping of the copper from the copper loadedchelate to form the electrolytic cell feed. The ratio of weights of theaqueous acid leach to the AQA-solvent in each stage is advantageouslywithin the range of about 10:1 to l:lalthough plants can be operatedoutside of this range. The rate of flow of the solvent phase is notnecessarily the same as the rate of flow as the aqueous acid leachsolution introducing the copper. With more stages, a more completelycopper loaded solvent phase, or strong acid phase is obtainaole, but thecost of equipment is higher.

EXAMPLE XVIII As illustrative shown in the drawing, an ore bedconsisting of the mine tailings form a copper mill was treated by slowlyspraying on the surface a dilute sulfuric acid solution in partconsisting of dilute sulfuric acid but mainly consisting of theextracted aqueous solution of leaching acid which penetrated slowlythrough the mine tailings, so that the leaching time was on the order ofmonths. As the aqueous acid leaching solution, now containing copper,slowly drains from the bottom of the mine tailing, the solution isfiltered to remove any solid particles and then fed into a liquidcountercurrent extraction column in which the feed volume is such thatapproximately one-third as rnust solvent phase is present as aqueousphase, with the aqueous phase running through the system somewhat fasterso that a major part of the copper os chelated with the 6-dodecylquinaldinic acid, dissolved at about percent by .weight in thesolvent phase. The solvent is 25 percent kerosene, with the boilingpoint range starting at 150 C. and about 70 percent of a liquid aromaticpetroleum fraction having a flash point of 150 F. and sold as Solvesso150" and 5 percent commercial grade isodecyl alcohol. The alcohol hasfrom C to C components, both branched and straight chain, but ispredominantly isodecanol. The 6-dodecylquinaldinic acid is from acommercial grade of para-dodecylaniline which contained an average ofabout 12 carbons in the side chain, but has species varying from about Cto C in the side chain.

The extraction is conducted at ambient mine temperature of about 65 F.with the extracted aqueous acid being recycled to the mine tailings andthe copper loaded chelate organic solvent being cycled to thecountercurrent stripper to which percent sulfuric acid plus recycledstrong acid was fed. The extracted organic solution AQA containing somecopper which was not stripped is recycled to the aqueous acid leachingextractor and the strong and the strong acid solution containing coppersulfate is fed to an electrolytic cell, as shown in the drawing. Thecopper is separated as electrolytic grade copper, with oxygen beingevolved at the other electrode. The electrolytic cell is of aconventional construction. To obtain higher current efficiency onlyaround 4050 percent of the copper is electrolized, with the restremaining in the strong acid which is recycled to the countercurrentstripping column.

Preferable operating embodiments in any one mill is in part controlledby the cost of electric poser, cost of the various chemicals, and oftenvaried to fit equipment which is already in the mill.

Those skilled in the art appreciate such interacting variants, and thefact that the ore bed can be any form of ore bed and frequently isvaried in a single mine over a period operation.

The copper chelates of the present long chain alkyl quinaldinic acidscan be represented by the formula:

where R,, R and R are each selected from the group consisting ofhydrogen and an alkyl group, and the total number of carbons in said R,R and R is at least about six, and not greater than about 30.

While the chelate formula appears to be a correct representation of thereaction product of the copper and the long chain alkyl quinaldinicacids, other formulas or representations may be used it is is thematerial and not the formula that is effective, and any difference inthe formula representing the material obviously has no effect on thecompounds themselves. I claim:

Iclaim 1. A process of recovering copper from aqueous acid leachsolution containing ore body impurities which comprises:

intimately mixing with an aqueous acid leach solution containing orebody impurities at least one water-insoluble, oil-soluble long chainquinaldinic acid having the formula N coon 4. The process of claim 2 inwhich the stripped said organic solvent containing said long chainquinaldinic acid is recycled to the mixing step, and the said solvent isa mixture of kerosene, an aromatic petroleum fraction, and not more than25 percent C to C alkanol.

5. The process of claim 4 in which the electrolyzed highly acidicsolution is recycled to the stripping step.

i k k t pun-no PAGE UNITED STATES PATENT @FFICE I CERTIFICATE 0FCORREC'HCN Patent No. 5,637,476 Dated January 25, 1972 lnventor(s)MICHAEL FANG It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 27, after the numeral "610" and before the word "Apr.please insert Column 1, line 28, after the word "News," and before theword "Apr., please delete Column 1, line 50, please change the number"3,244,875" to read ""5:22L|':875'- Column 2, line 75, after the word"million" and before the word "losses," please delete the word "reduced"and insert in its stead the words -to reduce--. I

Column 5, line 25, after the word "often" and before the word"commercially," please change the word "advantages" to readadvantageous-.

Column 5,, line 25, after the word "boiling" and before the word "the,"please change the word "that" to read --than--.

. Column 3, line 66, please insert a comma before the word "acids" andafter the word "copper."

Column l, lines 8 and 9, after'the word "quinoline. please delete thewords "substituted quinolines."

Column +,lines l2 and 15, after the word "yield," please delets the word"quinoline" and insert in lieu thereof the words -substitutedquinolines.

Column 4, line 45, second occurrence, please cancel the term "because."

R (10459) uscoMM-Dc seam-pan I ".5. GOVRNHENT PRINTNG OFFICE 1 9&90355-33.

PAGE 2 UNITED STATES, PATE OFCE CERTIFICATE OF C0 REQ Patent No 5 657476 Dated January 25 1,9 Z2

Inven-t01 '(s) MICHAEL FANG .It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 5, line 75, afterthe word "through," please change the word "the"'to read -and-'.

- Column line 58, please change the word "produce" .to read -produot'--Column 8, line 64, second occurrence, vplease cancel the term Column 8,line 72, before the word "slowly" the term "SnCl -2 O" should read--SnCl -2H O.

Column 9, line 1, the word "introduced" should read -introduce--.

Column 9, line 2, the word "aklylaniline" should read --alkylaniline--.

Column 9, line 19, the word "either" should read --ether-.

Column9, line 26, the w0rd"'introduced" should read -intro (11108"- 0 IColumn 9, line 27, the word "p-dodecylanilne", should read-pdodecylaniline-.

Column 9, line 37, "15o-14o0,o5" should read --130--1 +'o at O5"' aColumn 9, line 48, the word "milliliters" should read milli- 1iter.

FORM po'wso HO'GQ) uscoMM-oc scam-pm;

' 9 U. S. GOVENNHZNT PRINTING OFFICE 1909 0-366-334 PAGE 5 UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,637, 56 DatedJanuary 25, 1972 Inventor(s) MICHAEL PANG It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 9, line 55, the word "introduced" should read -introduce a Column9, line57, after the word "Add" and before the word "milliliters" pleaseinsert the number --222--.

Column 10, line 21, the word 'while" should read -white--.

Column 10, line 30, "3.77.4" should read "577.

Column 10, line 55, the word "taken" should read --takes--.

Column 10, line 56, after the word "hours" and before "20-25C.," pleaseinsert the word --at--'.

Column 10, lines 41 and 42, after the word "kilogram" and before theword "of" please insert the word "portions";

Column 10, lines +1 and 42, after the word "of" please delete the words"ether portions of."

Column 10, line 54, after the word "acid" and before the figure 7 "206,"please insert a comma Column 11, line 14, the word "ad" should read--as-.

Column .11, line 16, the word "graphs" should read g",

Column 11, line 51, after the word "solution" and before the word"kerosene," please delete the word "of" and insert in its stead the word--and--.

FORM M050 USCOMM-DC 60376-P69 ".5. GDVERNHENT PRINTING OFFICE I I9,0-356-34 PA GE a UNITED STATES PATENT OTTICE CERTIFICATE OF CORRECTECNPatent No. 5,637, 7 D t Janu ry 25, 1972 Inventor(s) MICHAEL PANG It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Columnll, line 72, the word "shown" should read -show Column 12, line27, please change "XiV" to read --XIV-.

" Column 12, line 28, the word "to" shouldread "in- Column 12, line 44,please change "XU" to read XV-.

Column 12, line &5, after the word "preceding, please add the following:-example XVI. The results were found to be Column 12, line 47, pleasedelete "EXAMPLE XVI."

Column 12,, line 49, please delete The results were found to be:

I Column 12, line 57, after the word "not" and before the word "readily"please insert the word as-.

Column 12, line 58, the word "from" should read -form--.

Column 12, line 58, after the word "be" and before the word "fairly,"please insert the word -a--.

Column 12, line 7'), "pr" should read --or--..

Column 13, line 2, the word "extraction" should read -extract an't--,

Column 15, lines 6 and 7, after the word "occurs" and before the word"in," please delete the words "naturally canyon impermeability."

FORM (1069) USCOMM-DC scam-ps9 ",5. GOVEnNHENT PHIHYING OF'lCE 2 I959Ol5$-314 PAGE 5 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTE-Patent No 3, 637, 476 I Dated January 25, 1972 Inventor(s) MICHAEL PANG-It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 13, line 11, after the word "impermeability," please insert aclosing parenthesis Column 13, line 18, please change the word "plate"to read place- Column 13 line 4 after the word'"illustrative" and beforethe word 'shown," please insert the word ;-and--.

Column 15, line 55, please change the word "must" to read --much--.,

Column 15, line 57, please change "os" to read "is",

Column 1 line 2, second occurrence, please cancel the-words "and thestrong."

Column 14, line 12', the word "poser" should read -power Column 14, line#4, after the word "used" and before the word "it," please insert a dashColumn 1 4, line 44, second occurrence, please delete the word Column14, line 47, please delete "I claim",

Column 14, line 66, after the word "six" and before the number "25,"please insert the words "to about,

Column 14, line 68, the word "the" should read --a-..

Signed and sealed this 7th day of November 1972.,

(SEAL) Attest':

EDWARD MJLETCHEIRJR. ROBERT GU'I'TSCHALK Attesting Officer Commissionerof Patents FORM P0-1050 (10-69) uscoMM-Dc 60376-P69 ".5. GOVERNMINTPRINTING OFFICE: 1989 O-366-S3A

2. The process of claim 1 in which the long chain quinaldinic acid is a6-alkyl quinaldinic acid with from about six to 20 carbon atoms in thealkyl group.
 3. The process of claim 1 in which the long chainquinaldinic acid is 6-dodecylquinaldinic acid, of a commercially puregrade.
 4. The process of claim 2 in which the stripped said organicsolvent containing said long chain quinaldinic acid is recycled to themixing step, and the said solvent is a mixture of kerosene, an aromaticpetroleum fraction, and not more than 25 percent C9 to C14 alkanol. 5.The process of claim 4 in which the electrolyzed highly acidic solutionis recycled to the stripping step.